Annual, dichotomously branched, rigid herb stem erect, terete, stout, scabrid, strigose and villous; radiculate leaves alternate, obovate-oblong, crenate, cauline leaves few, sessile, small, amplexicaul; heads homogamous, 2-5 flowered, sessile, forming a large terminal, flat-topped inflorescence, surrounded at the base by 3, cordate, leafy bracts; involucre compressed; bracts pungent, dry, stiff, about 8 leafy, alternately flat and conduplicate; all flowers equally 4-lobed, cleft on one side with the lobe spreading; corolla tubular, violet to purple; anther bases obtuse; style arms subulate; achenes truncate, 10 ribbed, hairy; pappus of 4-5, rigid, shining bristles, dilated at the base.